Aerial system



July 9, 1940. Q 3614 2,207,504

AERIAL SYSTEM Filed Dec. 21, 1938 41% MUM 11 Ki NI I I ZI 152i fwkwH'UWR INVENTQR OTTO BOHM ATTORNEY Patented July 9, 1940 2,207,504":

UNITED STATES PATENT OFFICE- AERIAL SYSTEM Otto Biihm, Hutton,Brentwood, England, assignor to Radio Corporation of America, acorporation of Delaware Application December 21, 1938, Serial No.247,004 In Great Britain December 24, 1937 10 Claims.

It is well known to obtain directional efiects in aerial systems byproviding at the end of an aerial conductor system a terminatingresistance which is equal to the surge impedance of said system so thatthe current in the system is in mitter T by a receiver. 5; one directiononly. Aerial systems of this kind Known aerial systems of the kindreferred to are well known and in general fall into one or and of whichthe above three known systems other of two classes, namely, that inwhich the are examples, sufi'er from the defect that there conductorsystem is essentially of the single is a considerable loss of energy inthe terminat-' conductor type and is earthed at the far end ing ohmicresistance. This defect is serious 10 through a resistance equal to thesurge impedboth in the case of transmission and in the case ance andthat in which the conductor system is of reception and the presentinvention seeks to essentially of the two conductor type, the twoovercome this defect by eliminating the ohmicconductors being connectedtogether at the far resistance in question. end through a resistanceequal to the surge im- According to this invention an aerial system 15;

pedance. In either class the aerial system may comprises two conductorsystems arranged close consist of the conductor system alone or the saidtogether so as to be tightly radiation coupled, conductor system may beprovided at suitable one of said system being directly arthed fintervals, with short, usually transverse radiators short circuited atthe far end and the other bein respect of which it acts as a feedersystem. ing left open circuited at the far end, and means 20 Threetypical known aerial systemsof the kind are provided for building p n ad Conductor in question will now be described and, with refsystemsstationarywaves of the same amplitude erence to Figures 1, 2 and 3 ofthe accompanying but with a mutual phase displacement of drawing, themanner in which these systems The easiest way to appreciatetheunderlying may be modified to be in accordance with this theory of theinvention is to consider what is invention will be described withreference to probably the simplest embodiment thereof, Figures 1A, 2Aand 3A of the drawing, Figure namely the case (not illustrated) wheretherelA showing the antenna of Figure 1 modified are two simple parallelstraight wires run closely according to the invention and similarly withadjacent to one another, one being directly respect to Figures 2A and3A. In the first of earthed at the far end and the other-being leftthese systems, Which is illust te y Figure open at the far end. Thewires are energized I there is e p yed simp y a Single Wire W1 which, atthe near ends by currents of the same ampliin the case of a transmitteraerial, is energized tud'e t in phase quadrature There 111 be at one endby a transmitter T and is earthed at current node a the end of one Wireand a the other through a resistance R equal to the current anti-node atthe far end of the other. 351 siiirge1 htfipedgnce. This1 iivire1 W1starts 3 f a l? The current I1 at the end of the earthed cona aieaovegroun eve,sopesup or a p its length to a point H of maximum height,and dilctor is gwen by the eXp-ressmn then slopes down to a little aboveground level I 005 t at its earthed end. In the second of these sys- )tw 9 tems-which is illustrated by Figure 2 two similar wires W1, We areemployed, these wires beg g i g wave length and x the distance ingarranged so that, in plan view, they together The current I2 at the endof the Open embrace a diamond shape except for the acute ductor is givenby v angled ends. The transmitter T is connected Y 45 between the wiresat one end i. e. at one acute 12:1 sin cos wt 4 I angled end of thediamond, and a resistance R 1 equal to the surge impedance is connectedSince the conductors are in close proximity tween the wires at the otherend of the diamond. and thus tightly coupled by radiation, the In thethird of these Systems illustrated by sult'ant effect is equivalent tothat of a single 50 Figure 3, two Straight, closely adjacent parallelconductor fed with the algebraic sum of the twoeS 1. W2, are providedWith Suitably Spaced currents I1 and I2. In other words, the resultshorttransverse radiators D1, Dc, those (D1) am urrent In may be written inthe form connected to one wire (W1) projecting to one 2 side and those(D2) connected to the other (W2) 1 i 55 projecting to the other. Eachradiator wire D1 I connected to one wire W1 is opposite to and in Thefirst of the three known systems (that'of' the same straight'line with aradiator wire D2 Figure 1), hereinbefore described, may be modiconnectedto We. The transmitter T is confied as shown in Figure 1A to be inaccordance nected between the wires W1, W2, at one end with thisinvention by dispensing with the earth- 86 and a resistance R, equal tothe surgeimpedance ing resistance R of Figure 1 (leaving the wire W1open at the far end) and providing a second,

- similar, conductor W1 closely adjacent the first conductor, anddirectly earthed at the far end.

Both conductors are energized, in the case of;a

transmitter, at their near end by currents of the same amplitude but inphase quadrature/ This energization is represented by two circlesrepresenting transmitters T1, T2 though in prac-' tice, of course, therewould probably be only one transmitter giving the required twoquadrature outputs.

The second of the three known systems hereinbefore described (that ofFigure 2) may be as shown in Figure 2A modified to be in accordance withthis invention by dispensing with the resistance R between the two wiresat one end of the diamond and providing another diamond arrangement oftwo wires W1, W2, adjacent the first wires W1 and W2 and similar theretoexcept that the two wires W1, W2 of the second diamond are directlyconnected together at the end where the Wires W1, W2 of the firstdiamond are left open. The two diamond arrangements are energized attheir near ends by currents of the same amplitude but in phasequadrature.

The third of the three known systems hereinbefore described (that ofFigure 3) may be modified as shown in Figure 3A to be in accordance withthis invention by dispensing with the resistance R at the ends of thetwo wires and providing a second two wire feeder and associated radiatorsystem closely adjacent the first. The second system is marked with thesame references as the first with prime marks af'ixed thereto. The twotwo-wire feeder and associated radiator systems are alike except that,in the second system the two wires of the feeder are directly connectedtogether at the far end while the radiators thereof are arranged to comemidway between the radiators of the first system. The two systems arefed in phase quadrature by currents of the same amplitude.

Any of the embodiments of this invention may be used for reception. Inthe case of a transmitter both systems in any embodiment may beenergized from the same source via any suitable amplitude and phasedetermining circuits as known per se, while, in the case of reception,the desired conditions can be realized by suitable coupling of the twosystems to av common receiver.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. An aerial system comprising two conductor systems arranged closetogether so as to be tightly radiation coupled, one of said systemsbeing directly earthed at the far end and the other being left opencircuitedat the far end, and means for building up on said conductorsystems stationary waves of the same amplitude but with a mutual phasedisplacement of 90.

2. An aerial system comprising two conductor systems arranged closetogether so a sto be tightly radiation coupled, one of said systemsbeing short circuited at the far end and the other being left opencircuited at the far end, and means for building up on said conductorsystems stationary waves of the same amplitude but with a mutual phasedisplacement of 90.

3. A system as claimed in claim 1 wherein there are two simple parallelstraight wires run closely adjacent to one another, one being directlyearthed at the far end and the other being left open at the far end.

conductor system comprises two similar wires so arranged as, in planview, to lie along the outline of a diamond shape.

6. A system as claimed in claim 2 wherein each conductor systemcomprises two straight, closely adjacent parallel wires provided withsuitably spaced short transverse radiators, those connected to one wireprojecting to one side and those connected to the other projecting tothe other, each radiator connected to one wire beingopposite and in thesame straight line with one connected to the other.

7. An aerial system comprising a pair of parallel straight wires closelyadjacent one another, whereby said wires are tightly radiation coupled,means connected to one end of said wires for energizing said wires withstationary waves of the same amplitude but with a mutual phasedisplacement of 90", one of said wires being earthed at its other end.

8. An aerial system comprising a pair of parallel wires arranged in avertical half diamond, said wires being closely adjacent one another,whereby said wires are tightly radiation coupled, means connected to oneend of said wires for energizing said wires with stationary waves of thesame amplitude but with a mutual phase displacement of 90, one of saidwires being earthed at its other end.

9. An aerial system comprising a pair of conductor systems arranged in ahorizontal plane with their ends adjacent and their mid pointsseparated, whereby a rhombic plan is formed, each of said conductorsystems comprising a pair of closely adjacent parallel wires, meansconnected to one end of said wires for energizing the wires of eachconductor system with stationary waves of the same amplitude, the energyin one wire of each conductor system having a phase displacement of 90from the energy in the other wire, one wire of one conductor systembeing connected to a wire of the other system carrying energy of thesame phase.

10. An aerial system comprising a pair of conductor systems arranged ina horizontal plane with their ends adjacent and their mid pointsseparated, whereby a horizontal diamond antenna is formed, each of saidconductor systems comprising a pair of soclosely adjacent parallel wiresthat said wires are tightly radiation coupled, means connected to oneend of said wires for energizing the wires of each conductor system withstationary waves of the same amplitude, the energy in one wire of eachconductor system having a phase displacement of 90 from the energy inthe other wire, one wire of one conductor system being connected to awire of the other system carrying energy of the same phase.

OTTO BOHM.

